Prior art workers have devised numerous types of automatic dishwashers, including undercounter dishwashers, top loading dishwashers, front loading dishwashers and the like. The teachings of the present invention are applicable to all such dishwashers. While not intended as a limitation, for purposes of an exemplary showing, the teachings of the present invention will be described in their application to a typical portable, front loading dishwasher for home use.
The typical automatic dishwasher for home use is equipped to carry on a series of operations in sequence. A series of operations is most commonly referred to as a "cycle". Modern automatic dishwashers are generally so arranged as to permit the operator to select the operations making up a desired cycle, from the full gamut of operations of which the machine is capable. A typical but non-limiting cycle may include the following operations: fill, first rinse, drain, fill, second rinse, drain, fill, wash, drain, fill, third rinse, drain, fill, fourth rinse, drain and dry. The desired series of operations or cycle is timer controlled, the timer turning on and off the various machine functions necessary for a given operation, determining the length of time each machine function is on or off, and thus determining the length of time for each operation of the cycle.
The typical front opening dishwashing for home use comprises a vat, having a large opening in the front end thereof. The vat is located in a cabinet or casing, provided with a hinged, downwardly opening front door which closes the large front opening of the vat during operation of the dishwasher. The vat is generally provided with upper and lower rail mounted racks for table and silverware, together with one or more spray arms. Pump means are provided to recirculate water within the vat and to drain the vat. The vat may also be equipped with a heating coil. Other appurtenances may be provided, including a detergent dispenser, door latch, safety switch and the like, all of which are well known in the art.
An automatic dishwasher of this type has an opening in one of the vat walls, generally located above the normal water level of the vat, to which a water inlet means is attached. U.S. Pat. No. 3,717,168, for example, teaches a typical water inlet unit. The water inlet unit is normally connected by a hose to a solenoid-controlled water valve, in turn connected to a water source.
Some economy models of automatic home dishwashers have very limited venting or air circulating means, although such ventilating means are desirable during the drying step to create cross ventilation within the vat. In some early models, during or immediately after the drying cycle, the dishwasher door opened a slight amount to ventilate the vat. It is also common practice to provide vent means in association with the dishwasher door. In such an instance, the door is made up of an exterior panel and an inner liner attached to each other in spaced relationship so that the door is in essence hollow. Vent openings are provided in the exterior panel near the upper end of the door and additional vent openings are provided in the door liner, near the bottom thereof. In such an instance, some air circulation will occur as a result of the chimney effect of the door.
Some models of automatic dishwashers for home use have been provided with blower means connected to an opening in one of the vat walls and generally used in association with door vent means. In some instances, the blower is used to withdraw hot moist air from the dishwasher vat, resulting in cooler dry air entering the vat through the door vent means. In other instances, the blower may be used to introduce cooler dry air into the vat, the hot moist air exiting through the door vent means.
The present invention is based upon the discovery that a water inlet nozzle, a vent stack, a blower and a blower housing can be combined into a single assembly connected to a single opening in one of the vat walls above the normal water level of the vat and preferably below the lower rack. Thus, two normally incompatible functions are combined in a single unit of simple and inexpensive construction, eliminating at least one opening in the vat, each vat opening constituting a potential leak source.
Furthermore, the vent stack and water inlet nozzle subcombination, without the blower and blower housing, can be used alone to introduce wash and rinse water into the dishwasher vat and to serve as a vent for the vat.